Write in a inequality that models a real world situation. describe your situation and what the variable x means

Atriangle has a side lengths of 18cm, 80 cm and 81cm. classify it as acute obtuse or right?

Molly shared a spool of ribbon with 12 people. each person received 3 feet of ribbon. which equation can she use to find r, the number of feet of ribbon that her spool originally had?

One number is 4 less than 3 times a second number. if 3 more than two times the first number is decreased by 2 times the second number, the result is 11. use the substitution method. what is the first number?